In a typical filter tipping machine, two-up tobacco rods are transferred along a series of drums for the execution of manufacturing steps which ultimately create, near the exit of the tipping machine, a succession of individual, filter tipped cigarettes that are discharged from a final, exit drum. Usually a stack-former apparatus is placed adjacent the exit drum of the tipping machine to initiate the formation of a moving, multi-layered mass of cigarettes. The stacked mass of cigarettes is then directed through a mass-flow elevator to the accumulator and/or a tray filler, which interfaces with a cigarette packer. Downstream of the stack-former, tracking of individual cigarettes is usually not possible.
Mass flow elevators of the prior art commonly comprise a pair of mutually opposing, vertically oriented endless belts which vertically transport the stacked (multi-layered) mass of cigarettes to a height that is conducive to feeding cigarettes to the packer and/or an accumulator or tray filler. It has been found that when one of the belts fail, the elevator may still continue to vertically transport cigarettes, but in a manner that increases the risk of skewed cigarettes, product degradation (e.g., flatten "D" shaped cigarettes) and machine jams downstream of the elevator.
Tipping machines of the prior art have included one or more quality inspection stations at a location along the cigarette stream where the individual cigarettes have been fully formed and separated from one another. Typically, these devices inspect the cigarettes for loose ends, proper rod density, missing filters and other quality-indicative features. Because cigarettes are not fully constructed until close to the exit station of the tipping machine, there is but little room and opportunity for the placement and operation of the inspection devices and for effecting rejection of unacceptable cigarettes (i.e., cigarettes which have failed to pass one or more of the aforementioned quality inspection tests). There is also little or no room nor time for confirmation of a detector's initial reading.
Because cigarettes were heretofore mixed amongst each other soon after the exit of the tipping machine, all rejections of unacceptable cigarettes had been effected within the tipping machine, typically at a single rejection station at a fixed location along a single drum (usually the exit drum or a dedicated rejection drum just upstream of the exit drum). At the rejection station, a blast of compressed gas would be communicated to an underside of a passing flute known to carry an unacceptable cigarette by the flute tracking system of tipping machine controller. The blast is gauged to be sufficient to overcome the vacuum retention system of drum so as to blow the cigarette off the respective drum flute. Because the blast has to be complete and so immediate in so little space and time, the ejection process often rips or otherwise further damages the rejected cigarettes. The additional damage also tends to mask the true condition of the cigarette as it appeared at the inspection station, hampering resolution and correction of the causal problem at the cigarette maker.
Also, prior ejection systems heightened the risk of jams, because all ejections, for whatever reason out of a multiple of reasons, had to be undertaken at the exit station amongst a host of high speed, complicated rotating machinery. Additionally, if a consecutive series of cigarettes failed inspection, the repetitious operation of the rejection system would degrade its performance and/or tend to interfere with the vacuum retention system of the machine.
Heretofore, sampling of good cigarettes included the practice of a machine operator manually scooping a sample of cigarettes from the stacked mass. The scooping action has been found to occasionally skew cigarettes along the stack and to sometimes damage product.